Antihistamines are medications used for the treatment of allergies, cold and flu symptoms, including sneezing, watery eyes, coughing, hives, runny nose and more. These medications are available by prescription and over the counter. Warning labels on antihistamines caution against drinking alcohol while taking medication, especially if you are a daily drinker. Further, laws are in effect in many states banning the use of an automobile when under the influence of a sedating drug or alcohol.
One of the main side effects of antihistamines is a feeling of sedation, according to Columbia University's health information website, Go Ask Alice. Combined with the effects of alcohol, taking the two simultaneously could magnify the effects, posing a possible danger when watching children, operating a motor vehicle or other machinery. While newer antihistamines do not have the same sedative effects, there is a risk of low blood pressure and falls in seniors. Again, that risk is compounded with alcohol.
Combining alcohol with antihistamines can cause drowsiness, dizziness and increased risk for overdose, according to the National Institute on Alcohol Abuse and Alcoholism. Antihistamines are often combined with pain relievers and decongestants, reports the American Academy of Family Physicians. Taking alcohol with a painkiller can result in stomach upset, bleeding, ulcers, liver damage and rapid heartbeat.
First generation antihistamines, such as diphenhydramine and fexofenadine can cause more severe impairment when combined with alcohol than being legally drunk, according to researchers from the University of Iowa. In the 2000 study, researchers tested volunteers' alertness on a driving simulator after taking a first-generation cold drug in addition to alcohol. The participants were unable to gauge their level of impairment. Newer antihistamines, or second-generation drugs, do not seem to have the same effect when taken with alcohol.
Blood Alcohol Level
One of the most concerning dangers when combining antihistamines with alcohol is that compared to beer, the alcohol content in wine is higher. A serving of beer contains 4 to 5 percent alcohol. A serving of wine has 12 to 15 percent alcohol – and more for imported wines. A 180 lb. male could be consider legally intoxicated after drinking four glasses of wine over the course of an hour. A 120 lb. female may be considered impaired after drinking two to three glasses of wine over the same amount of time. Taking an antihistamine can worsen your impairment and you many not be aware of it.
- Drugs.com: Antihistamines
- National Institute on Alcohol Abuse and Alcoholism; Harmful Interactions, Mixing Alcohol with Medicines
- ScienceDaily: First-Generation Antihistamine Has More Impact Than Alcohol on Driving; March 2009
- Montclair State University: How Much Alcohol is in My Drink?
- Blood Alcohol Calculator